This application is based on applications Nos. 9-348939 and 10-193001 filed in Japan, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a message receiving apparatus for receiving messages converted for secret communication, and a message transmitting apparatus for transmitting the converted messages.
2. Description of the Prior Art
In computer-to-computer communications, encryption techniques are widely used to protect privacy of information against third parties aside from the transmitter and the receiver of the information. Digital signature techniques which add signature information to transmission information are equally widely used to guarantee secure information transmission from the transmitter to the receiver.
For example, in the WWW (World Wide Web) system on the Internet, encryption techniques can be used when a user of a client apparatus inputs a message of a predetermined format in response to information provided from a server apparatus and transmits the input message to the server apparatus. The SSL (Secure Socket Layer) protocol and the S-HTTP (Secure-HyperText Transfer Protocol) are representative of such encryption techniques used in the WWW system.
To communicate a message which requires privacy using the SSL protocol, first a server (receiver of the message) sends a request to select whether to use the SSL protocol to a client (transmitter of the message), and the client accordingly selects to use the protocol (that is, to encrypt the message) and sends a list of available encryption methods to the server. After the server selects one of the available encryption methods, the message communication begins between the server and the client using the selected encryption method.
Thus, in message communication using the SSL protocol, to perform encrypted message communication depends on the client""s decision to encrypt the message. Similarly, when using other conventional encryption techniques, encrypted communication is performed depending on whether the client chooses to perform encryption. This dependency on the client to decide whether to perform encryption often places a constraint on the performance of the server.
The present invention aims to provide a message receiving apparatus that determines whether to perform encryption/digital signature on each input message in a message transmitting apparatus according to conditions under which the message is transmitted from the message transmitting apparatus, and the message transmitting apparatus that transmits messages to the message receiving apparatus.
In order to fulfill the above object, the message receiving apparatus of the present invention is a message receiving apparatus for receiving messages from a message transmitting apparatus, the message receiving apparatus including: a first generating unit for generating first data for producing a display which urges a user of the message transmitting apparatus to input a message; a second generating unit for generating second data within the first data for specifying a conversion type for secret communication of the message; a transmitting unit for transmitting the first data including the second data to the message transmitting apparatus; and a receiving unit for receiving the message from the message transmitting apparatus after the first data including the second data has been transmitted to the message transmitting apparatus.
With this construction, the message receiving apparatus generates the first data for producing the display that urges the user of the message transmitting apparatus to input the message, generates the second data within the first data for specifying the conversion type for secret communication of the message, transmits the first data including the second data to the message transmitting apparatus, and subsequently receives the message from the message transmitting apparatus.
Thus, the message receiving apparatus can, according to its intentions such as improvement of the security in communication, freely specify the conversion type for secret communication of the message to be sent from the message transmitting apparatus. Also, the message receiving apparatus can specify a conversion type for each of a plurality of messages to be sent from the message transmitting apparatus.
The above object can also be fulfilled by a message receiving apparatus for receiving messages from a message transmitting apparatus, the message receiving apparatus including: a first receiving unit for receiving first data concerning a use condition of the message transmitting apparatus from the message transmitting apparatus; a first generating unit for generating second data for producing a display which urges a user of the message transmitting apparatus to input a message; a second generating unit for generating third data for specifying a conversion type for secret communication of the message according to the received first data; a transmitting unit for transmitting the second data and the third data to the message transmitting apparatus; and a second receiving unit for receiving the message from the message transmitting apparatus after the second data and the third data have been transmitted to the message transmitting apparatus.
With this construction, the message receiving apparatus receives the first data concerning the use of the message transmitting apparatus from the message transmitting apparatus, generates the second data for producing the display which urges the user of the message transmitting apparatus to input the message, generates the third data for specifying the conversion type for secret communication of the message according to the first data, and transmits the second data and the third data to the message transmitting apparatus. The message receiving apparatus subsequently receives the message from the message transmitting apparatus.
Accordingly, the message receiving apparatus with intentions such as improvement of the security in communication can by itself specify the conversion type for secret communication of the message according to the use condition of the message transmitting apparatus.
Here, the message receiving apparatus may further include an associating unit for associating the first data with conversion type information that indicates whether to perform encryption, which encryption method should be used if performing the encryption, whether to perform digital signature, and which digital signature method should be used if performing the digital signature, wherein the use condition of the message transmitting apparatus shown by the first data corresponds to an attribute of the user of the message transmitting apparatus, and wherein the second generating unit generates the third data according to the conversion type information associated with the first data.
With this construction, the message receiving apparatus, on receiving the first data concerning the user attribute of the message transmitting apparatus, generates the third data according to the conversion type information associated with the first data, the conversion type information indicating whether to encrypt/digitally sign the message and which encryption/digital signature method should be used. The message receiving apparatus then sends the second data and the third data to the message transmitting apparatus and subsequently receives the message converted by the message transmitting apparatus according to the third data.
Accordingly, the message receiving apparatus can specify whether to encrypt/digitally sign the message and which encryption/digital signature method should be used, based on the user attribute of the message transmitting apparatus.
Here, the second data may be written in an HTML format, wherein the third data is written within the second data using tags that extend the HTML format.
With this construction, the message receiving apparatus, on receiving the first data, generates the second data written in the HTML format and further generates the third data within the second data using the tags according to the first data.
Accordingly, the message receiving apparatus can specify whether to perform encryption/digital signature and which encryption/digital signature method should be used for the message by adding the special tags to the document written in HTML, based on the user attribute of the message transmitting apparatus. Thus, a conversion type can easily be specified for each of a plurality of messages by adding such special tags to an HTML document.
Here, the message receiving apparatus may further include a storing unit for storing fourth data showing key information necessary for the message transmitting apparatus to perform the encryption, wherein the transmitting unit transmits the second data, the third data, and the fourth data to the message transmitting apparatus.
With this construction, the message receiving apparatus transmits the fourth data showing the key information necessary for the encryption to the message transmitting apparatus along with the second data and the third data. Accordingly, the message receiving apparatus can easily specify the encryption method which uses the key information.
Here, the message receiving apparatus may further include a reconverting unit for reconverting the message received by the second receiving unit.
With this construction, the message receiving apparatus, after sending the second data and the third data to the message transmitting apparatus, receives the message which has been converted by the message transmitting apparatus according to the conversion type specified by the third data and reconverts the received message. Accordingly, the message receiving apparatus can perform secret communication of the message with the message transmitting apparatus with greater convenience by reconverting the received message.
Here, the conversion type specified in the third data may indicate whether to perform encryption, which of encryption methods set in advance in the message transmitting apparatus should be used if performing the encryption, whether to perform digital signature, and which of digital signature methods set in advance in the message transmitting apparatus should be used if performing the digital signature.
With this construction, the message receiving apparatus generates the third data according to the first data received from the message transmitting apparatus, the third data including an indication concerning whether to perform encryption/digital signature and which of encryption/digital signature methods set in advance in the message transmitting apparatus should be used.
Accordingly, the message receiving apparatus can specify whether to encrypt/digitally sign the message and which of encryption/digital signature methods set in the message transmitting apparatus should be used, based on the use condition of the message transmitting apparatus.
Also, to fulfill the above object, the message transmitting apparatus of the present invention is a message transmitting apparatus for transmitting messages to a message receiving apparatus, the message transmitting apparatus including: a receiving unit for receiving first data for producing a display which urges a user of the message transmitting apparatus to input a message from the message receiving apparatus, the first data including second data for specifying a conversion type for secret communication of the message; a displaying unit for producing the display according to the first data; an inputting unit for receiving the message inputted by the user in response to the display; a converting unit for converting the input message according to the second data; and a transmitting unit for transmitting the converted message to the message receiving apparatus.
With this construction, the message transmitting apparatus receives, from the message receiving apparatus, the first data for producing the display which urges the user to input the message and the accompanying second data for specifying the conversion type for secret communication of the message. The message transmitting apparatus then produces the display according to the first data, receives the message inputted by the user in response to the display, and converts the input message according to the second data. This converted message is then transmitted to the message receiving apparatus.
Accordingly, the message transmitting apparatus can convert the message according to the conversion type which has been specified by the message receiving apparatus with intentions such as improvement in the security in communication.
The above object can also be fulfilled by a message transmitting apparatus that outputs first data for producing a display to a displaying unit and transmits a message, inputted by a user via an inputting unit in response to the display, to a message receiving apparatus, the message transmitting apparatus including: a receiving unit for receiving the first data for producing the display which urges the user to input the message from the message receiving apparatus, the first data including second data for specifying a conversion type for secret communication of the message; a converting unit for converting the message inputted by the user according to the second data; and a transmitting unit for transmitting the converted message to the message receiving apparatus.
With this construction, the message transmitting apparatus receives, from the message receiving apparatus, the first data for producing the display which urges the user to input the message and the accompanying second data for specifying the conversion type for secret communication of the message. The message transmitting apparatus then outputs the first data to the displaying unit, converts the message inputted via the inputting unit in response to the display according to the second data, and transmits the converted message to the message receiving apparatus.
Accordingly, the message transmitting apparatus can convert the message according to the conversion type, that has been specified by the message receiving apparatus with intentions such as improvement of the security in communication, through the use of the existing displaying and inputting units.
The above object can also be fulfilled by a message transmitting apparatus for transmitting messages to a message receiving apparatus, the message transmitting apparatus including: an acquiring unit for acquiring first data concerning a use condition of the message transmitting apparatus; a first transmitting unit for transmitting the first data to the message receiving apparatus; a receiving unit for receiving, from the message receiving apparatus, second data for producing a display which urges a user to input a message and third data, generated according to the first data, for specifying a conversion type for secret communication of the message; a displaying unit for producing the display according to the second data; an inputting unit for receiving the message inputted by the user in response to the display; a converting unit for converting the input message according to the third data; and a second transmitting unit for transmitting the converted message to the message receiving apparatus.
With this construction, the message transmitting apparatus acquires the first data concerning the use of the message transmitting apparatus and transmits the first data to the message receiving apparatus. The message transmitting apparatus then receives the second data for producing the display which urges the user to input the message and the third data, generated according to the first data, for specifying the conversion type for secret communication of the message from the message receiving apparatus, and produces the display according to the second data. On receiving the message inputted by the user in response to the display, the message transmitting apparatus converts the input message according to the third data and transmits the converted message to the message receiving apparatus.
Accordingly, the message transmitting apparatus can convert the message according to the conversion type specified by the message receiving apparatus with intentions such as improvement of the security in communication. Also, since the conversion type has been determined by the message receiving apparatus based on the use condition of the message transmitting apparatus, the message can be converted in accordance with the conversion type appropriately specified by the message receiving apparatus.
Here, the message transmitting apparatus may further include an associating unit for associating the third data with conversion type information that indicates whether to perform encryption, which encryption method should be used if performing the encryption, whether to perform digital signature, and which digital signature method should be used if performing the digital signature, wherein the converting unit converts the input message according to the conversion type information associated with the third data.
With this construction, the message transmitting apparatus converts the input message according to the conversion type information indicating whether to perform encryption/digital signature and which encryption/digital signature method should be used.
Accordingly, the message transmitting apparatus can encrypt and/or digitally sign the message according to an indication, made appropriately by the message receiving apparatus according to the use condition of the message transmitting apparatus, concerning whether to perform encryption/digital signature and which encryption/digital signature method should be used.
Here, the second data may be written in an HTML format, wherein the third data is written within the second data using tags that extend the HTML format.
With this construction, the third data received together with the second data is written within the second data of the HTML format using the tags that extend the HTML format. Accordingly, the message transmitting apparatus can encrypt and/or digitally sign the message according to an indication which can be made easily by the message receiving apparatus by adding the special tags to the HTML document and transmitting the document to the a message transmit ting apparatus.
Here, the message transmitting apparatus may further include a preventing unit for preventing the third data written using the tags from being displayed.
With this construction, the third data written within the second data using the tags is not displayed on the screen of the message transmitting apparatus. Since the third data specifying the conversion type is not displayed on the screen, it is possible to prevent the specified conversion type from being changed in the message transmitting apparatus.
Here, the receiving unit may receive fourth data showing key information necessary for performing the encryption from the message receiving apparatus together with the second data and the third data, wherein the converting unit converts the input message according to the third data and the fourth data.
With this construction, the message transmitting apparatus converts the message using the key information shown by the fourth data according to the conversion type information associated with the third data. Accordingly, the message transmitting apparatus can easily encrypt the input message using the received key information necessary for the specified encryption method.